This research aims to describe the development process of a problem-based learning management system-supported smartphone (PBLMS3) application using the ADDIE Model (analysis, design, development, implementation, and evaluation) and to determine its effectiveness in improving digital literacy. Data were collected from 40 physics education students in Tasikmalaya, consisting of 13 males and 27 females with an average age of 20 years. Data collection techniques included a literature study, expert validation, digital literacy test, and a questionnaire on student perceptions. Expert validation was obtained from three experts using a Likert scale and processed by the validation value equation developed by Aiken. The expert validation resulted in a value of 0.92, which met the minimum validation requirements. Furthermore, the effectiveness of the PBLMS3 application in improving digital literacy in online physics learning was determined by a statistical process using the Wilcoxon test. Based on its results, the t-value was 0.4752, with a p-value of 0.00 < 0.05. This means that the PBLMS3 application is effective for and capable of improving students’ digital literacy. Further research is recommended to determine other factors capable of improving digital literacy.